The present invention relates to a safety syringe particularly equipped with a needle receiving tube which safely facilitates the mounting and dismounting of a disposed needle. The safety syringe has a container, an injection rod, a needle and a needle receiving tube. The needle can be withdrawn into the container via rotation of the injection rod after being used for disposal so as to protect hospital personnel from being accidentally punctured by a disposed needle which can cause fatal contagion of various diseases. The container is provided with a protruded needle mounting neck having a lid attached to the edge thereof. The injection rod housed in the container has a rubber piston head which is provided with a plunger end. The plunger end is made up of 4 symmetric plane extensions each having a round projection on the edge of each plane extension. The needle has a slantly cut shot end and a threaded engagement bottom end which is internally provided with 4 symmetric plane lugs and a protruded ring at the edge thereof for retaining purpose. The plunger end of the injection rod can firmly engage with the bottom end of the needle in the mounting and dismounting of a needle housed in a needle receiving tube so as to protect a hospital personnel from being accidentally punctured by a disposed needle.
There have been many hospital related personnel suffering from fatal contagion of various diseased as a result of accidentally punctured by disposed needles, such as AIDS, TB and diseases of the like, which are distributed via blood. So, it is a life and death matter for doctors and nurses to deal with disposed needles within hospitals and clinics.
To better protect hospital personnel from being fatally punctured by disposed needles, a number of safety syringes have been designed and marketed for many years. The most common safety syringes on markets are made up of more than 4 pieces, causing the production cost of syringes to increase in one aspect and to burden the natural enviroment when disposed without processing in another aspect. So, it is not popularly used at all.
Furthermore, another type of safety syringe as illustrated in FIGS. 1, 2, such a prior art safety syringe is made up of a tubular container 1, an injection rod 2, a needle 3 and a needle cover (not shown). The tubular container 1 has a needle mount 10 for the retaining of the needle 3 at one end and has an oval shaped stop flange 11 at the other end. A limiting plate 12 having a retaining recess 13 at its edge extends from one side of the stop flange 11. The injection rod 2 having a cross-shaped section is slidably housed in the tubular container 1. At the front end of the injection rod 2 is disposed a piston end 20 having a mushroom-shaped retaining piece 21 at one end and at the other end of the injection rod 2 is disposed a circular disk 22. On two opposite points of the periphery of the circular disk 22 are disposed a retaining piece 23 respectively which is engaged with the retaining recess 13 of the limiting plate 12 of the tubular container 1.
The needle 3 has a slantly cut puncturing end 30 and the other end of the needle 3 has an outerly threaded tube 31 having a pair of opposite openings on the wall thereof. There are two slant retaining claws 32a, 32b housed in the threaded tube 31 and extending from the edge of the openings respectively, as shown in FIG. 1, so as to permit the mushroom shaped retaining piece 21 to be locked in place by the retaining claws 32a, 32b. The slant angles of the retaining claws 32a, 32b are not identical. When the injection rod 2 is pulled backward, the needle 3 can be withdrawn into the tubular container 1 after the needle 3 is rotated to disengage from the needle mount 10. The needle will lean to one side as a result of the difference of the slant angles of the retaining claws 32 when it is pulled into the tubular container 1. Afterwards, the needle mount 10 is closed by the needle cover (not shown) so as to protect hospital personnel from being pricked by disposed needles which are withdrawn into the tubular container after use.
Such a prior art safety syringe has the following disadvantages in its design and practical use:
1. The needle is easily subject to contamination after it is taken out from its germ-free packing by hospital personnel wearing no gloves and exposed to the air. PA0 2. The needle cover is easily dropped and the exposed needle can get people pricked accidentally. PA0 3. The retaining claws are made in a relatively complex manner having too many cuts and corners in which residues produced in a manufacturing process can be hidden and injected into a patient's body via blood vessels, causing unexpected diseases. PA0 4. The injection rod can not be pushed fully to the bottom end of the tubular container, making medical liquids unable to be fully and efficiently injected into patients' bodies. PA0 5. The tubular container is not provided with slippery proof strips; a person exerting a large force to withdraw the injection rod and get a disposed needle pulled into the tubular container will easily get pricked by a used needle as a result of slippery of his or her hands off the tubular container.